This application pertains to the art of filters and more particularly to fluid type filters.
The invention is particularly applicable to an in-line type welded filter design and will be described with particular reference thereto. However, it will be appreciated by those skilled in the art that the overall invention has broader applications and could be adapted to use for other applications in different environments.
Heretofore, there have been quite a number of different types and styles of fluid filters, including in-line type fluid filters. Among these have been the so-called multi-piece welded filter constructions wherein a pair of filter body sections are disposed in an end to end relationship with a filter element interposed and partially captured therebetween. The two filter body sections are welded together peripherally around end face or shoulders. Such welding also fixedly retains the filter element in position generally transverse across a filter chamber defined internally of the body sections. The body sections each include means for conveniently installing the filter in a fluid system so that fluid entering the fluid inlet will be filtered prior to exiting from the filter outlet.
Prior welded type in-line filters have utilized various filter element constructions, including those of a pleated or accordian configuration. In such filter element configurations, the filter element material is formed to have a plurality of closely spaced alternating folds with the filter material between adjacent folds extending generally longitudinally of the filter itself. This increases the surface area of the filter element material exposed to fluid passing through the filter, and thus enhances filter efficiency.
While the above noted multi-piece welded fluid filters have found use and acceptance in a wide variety of fluid or liquid filtering environments and systems, certain problems are encountered when these filters are installed in high pressure fluid systems and/or subjected to differential fluid pressures. These prior filter constructions have typically been able to withstand a maximum differential pressure across the filter element on the order of magnitude of approximately 50 psi. Differential pressures are typically encountered when the filter element begins to clog, when there are high surge pressures in the system, when a high fluid flow or a viscous liquid flow is involved and when there is a pulsating type of fluid flow in the system. In the event the pressure differential across the filter element exceeds the allowable maximum, the filter element itself can be permanently damaged so that it is ineffective for its fluid filtering function.
In addition, when filters of the multi-piece welded type are subjected to high fluid pressures, i.e., on the order of magnitude of 6000 psi or so, it is particularly necessary and desirable to have the fitting body sections interconnected in a manner that will insure a connection of high integrity. Without such a connection, it is possible that the filter may fail at less than the rated pressure capabilities.
The present invention contemplates a new and improved device which overcomes these problems and others and provides a new and improved in-line fluid filter of the multi-piece welded type which is simple, reliable at elevated operating pressures, increases the allowable differential pressure across the filter element and which is readily adapted to use in a number of fluid or liquid environments.